"All I can say is that this is where politics is at. Do I feel strongly about it? Yes, I do. Am I very motivated by that? Yes. Where do I go from here? What exactly do I do? That's an open question."

As leader of the Labour party, Mr Blair won three consecutive general elections from 1997 onwards on a platform of centrist policies.

The party has since shifted sharply to the left under veteran socialist Jeremy Corbyn, a strident opponent of the Iraq war and of Mr Blair himself.

Mr Blair acknowledged there had been "a huge reaction" against his brand of politics but said that centrists must fight back.

"I think it's too soon to say the centre has been defeated," he said.

"We've got to rise to that challenge".

Last year, Mr Blair said he felt "more sorrow, regret and apology than you may ever know or can believe" after the Chilcot report found the invasion of Iraq was based on flawed evidence and badly executed.

Pollsters YouGov have found that Mr Blair currently has a public perception rating of -63, with people they surveyed who disliked him describing him as "self-serving" and "money-grabbing".

Last month, Mr Blair announced he was winding up Tony Blair Associates, his advisory business, which has worked with countries including oil-rich Kazakhstan and its autocratic President Nursultan Nazarbayev.